Question

Which of the following can be the sides of a right triangle?

(i) 2.5 cm, 6.5 cm, 6 cm

(ii) 2 cm, 2 cm, 5 cm

(iii) 1.5 cm, 2 cm, 2.5 cm

In the case of right-angled triangles, identify the right angles.

Answer 1

I) as you can see 2.5^2+6^2=6.5^2
L.h.s=2.5^2+6^2
= 6.25+36
=42.25
=6.5^2=r.h.s
Therefore right angle triangle
2) 2^2+2^2=8 and 5^2=25
They are not equal, therefore not right angle triangle
3) 1.5^2+2^2=2.25+4
=6.25
=2.5^2
Therefore it is a right angle triangle

Answer 2

since sum of any two sides of a triangle is greater than 3rd third
here 1) 2.5+6> 6.5
2) 2+2<5
3) 1.5+2=2.5

so( 1) is a triangle and it is also right angled triangle by Pythagoras theorem
2.5^2+ 6^2
=6.25+36
=42.25
=6.5^2